Packer with shear member



March 26, 1968 H. CURRENT 3,374,841

PACKER WITH SHEAR MEMBER Filed Oct. 22, 1965 2 Sheets-Sheet 1 James(u/rent INVEN'J'OR.

March 26, 1968 J. H. CURRENT 3,374,841

PACKER WITH SHEAR MEMBER Filed Och 22, 1965 I 2 Sheets-Sheet 2 zlme: h.Curve/7f INVIiNJUR.

A 7TOR/VE y United States Patent 3,374,841 PACKER WITH SHEAR MEMBERJames H. Current, Houston, Tex., assignor to Schlumberger Well SurveyingCorporation, Houston, Tex., a corporation of Texas Filed Oct. 22, 1965,Ser. No. 500,946 3 Claims. (Cl. 166-138) ABSTRACT OF THE DISCLOSURE Theparticular embodiment described herein as illustrative of one form ofthe invention in well tools includes a mandrel with a packing elementmounted thereon for packing off a well bore. An abutment engages one endof the packing element for exerting compression force thereon, and isreleasably coupled to the mandrel by a shear member which normallyprevents relative movement between the abutment and body, but which isresponsive to a predetermined force to uncouple the abutment andmandrel. The shear member can be weakened along radial lines to permitsegments thereof to be conveniently removed in order to selectivelychange the predetermined force necessary to uncouple the mandrel andabutment.

This invention relates to a well tool and, more particularly, to apacker apparatus for use in a well bore.

In the drilling and production of oil wells, it is often necessary toisolate zones or formations in the well bore in order to produce fromand to permit or prevent the treating of such selected zones. Theisolation of such zones or formations is commonly done by use of packersor bridge plugs. The present invention is primarily concerned with atubing-type retrieval packer for use in a cased well bore. Such packersnormally include a slip and drag block assembly in combination with apacker element. The packer is set by first unlocking a jaying mechanismand then applying tension or compression to the running in tubing whichsequentially sets the slips into the well casing and expands the packerelement. The expanded packer element seals off an annulus between thecasing and the body of the packer. At some later time, the packer may beretrieved by manipulating the tubing to sequentially contract the packerelement and unlock the slips from the casing. The packer is then lockedin an inactive position by the jaying mechanism and retrieved to thesurface.

In the event the packer should become stuck, a shearing device isusually provided between the packer body and the assembly holding thepacker element. By applying greater than normal forces to the tubingstring, the stuck parts can be made to shear from the body so that thebody portion of the packer may be retrieved. The remainder of the toolis then fished or drilled out.

In the construction of such packers, it is important to maintain theapparatus as simple as possible for the reason that the more complicatedthe mechanism may be, the more likelihood there is that the mechanismwill malfunction and prevent the retrieval of the packer by normalmeans.

It has been found that springs used for operating the slips and dragblocks are particularly susceptible to corrosive action of well fluidsand often fail to operate. The failure of the springs to operate maycause the packer to become stuck in the well. Non-corrosive springs onthe other hand are expensive and further add to the cost of the packer.In a typical packer, the slip and drag block assembly may be comprisedof six slips, six slip pins, six drag blocks and eighteen springs; eachbeing separate parts. Cost and susceptibility to malfunction arenormally proportional to the number of individual parts comprising theassemblies. Where such packers are left in the well bore for use overextended periods of time, the cost of manufacture of the packer becomeseven more important.

It is, therefore, an object of the present invention to provide a newand improved packet which is economical to construct and simple in itsoperation.

With this and other objects in view, the present invention relates to apacker having a resilient element expandable by virtue of relativemovement between upper and lower gauge rings. An expander coneassociated with one of the gauge rings actuates slips to provide a rigidstop for that gauge ring against which movement of the other gauge ringcompresses the resilient element and thereby laterally expands theelement into engagement with the well. Slip and drag block means areconstructed as a single unit. The drag block means permits a jayingmechanism to be operated, which, in turn, provides for relative movementbetween the slips and expander cone.

Shear means are provided between one of the gauge rings maintaining thepacker element expanded and the packer mandrel so that should theapparatus become stuck in the well bore, the shear ring may be shearedto let the packer element collapse and permit removal of the tool fromthe well. The shear ring is so constructed as to permit a convenientselection of shearing forces.

A complete understanding of this invention may be had by reference tothe following detailed description when read in conjunction with theaccompanying drawings illustrating an embodiment thereof, wherein:

FIG. 1 shows a partial sectional view of a packer embodying features ofthe present invention;

FIG. 2 shows a partial sectional view of a packer utilizing analternative slip and drag block arrangement;

FIG. 3 shows a sectional view of part of a packer illustrating ashearing mechanism;

FIG. 4 is a sectional view taken along lines 6-6 of FIG. 3; and

FIG. 5 is a side view of the shearing device shown in FIGS. 3 and 4.

Referring to FIG. 1, the packer apparatus is comprised of a mandrel orbody 12 which is threaded at its upper end for connection to a string oftubing. An elastomer packer element 14 is positioned about the body andis supported on one end by an upper gauge ring 16 which, in turn, isconnected to the mandrel by a shear pin or shear ring 18. The other endof the packer element is supported by a combination gauge ring andexpander 20. The gauge ring and expander 20 is supported on the mandrelby means of an annular shoulder 22 extending outwardly from the mandrel.

A unitary member 24 is arranged about the packer mandrel below theexpander. This unitary member has portions thereon serving as slips anddrag blocks. The member is preferably machined or otherwise formed of asingle piece of material. An upper portion 26 of this unitary member hasteeth 28 formed therein to render the upper portion operable as slips.The upper end of the slip portion 26 has an inwardly sloping surface 30thereon which mates with an outwardly sloping surface 32 formed on theexpander 20. These sloping surfaces are arranged so that relativemovement of the slip and expander toward one another will cause the slipto cam outwardly into engagement with the well casing. An enlargedportion 34 at the other end of the unitary member forms ad rag blockmeans for frictionally engaging the interior of the well casing. Aplurality of longitudinal slots 36 are formed through the unitary memberWith adjacent slots running from alternate ends of the member to aterminal point 38 near the opposite end. The terminal point is in theshape of a hole through the member which serves as a stress reliefmeans. This arrangement of slots in the unitary member permits themember to be compressed and thus reduced in size or diameter upon theapplication of radial forces inwardly against the member. A space 40 isprovided between the unitary member and the mandrel to permit suchradial compression. The lower end of the unitary member is supported bya drag block cage 42 having a hook-shaped annular lug 44 extendingupwardly therefrom. The hook portion 46 on the lug is received within arecess 48 at the lower end of the unitary member. An inwardly extendingJ pin 50 which is attached to the drag block cage 42 is slidablyreceived within a conventional J-slot 52 normally used with such packerdevices.

In the operation of the apparatus shown in FIG. 1, the packer is loweredinto the well bore to a depth where it is desired to expand the packeragainst the wall of the wall. At this point, the packer mandrel israised upwardly and rotated to place the J-pin 50 into a longlongitudinal section of the J-slot 52. The mandrel is then lowered withthe pin 50 riding upwardly in the long section of the I-slot. The J-pin50 is held from downward movement with the mandrel by frictionalengagement of the drag block 34 against the wall of the well. Relativemovement between the mandrel and unitary member, on which the drag blockis formed, causes the sloping portion 30 of the slip to ride upwardly onthe surface 32 of the expander thereby caming the slips outwardly intogripping engagement with the well bore. Further downward movement of themandrel pushes the upper gauge ring, packer element, and lower gaugering expander against the now-anchored slips and compresses theelastomer packing element between the upper and lower gauge rings. Suchcompression of the ends of the packer element causes the element toexpand radially outwardly into sealing engagement with the wall of thewell.

What it is desired to unset the packer, weight is picked up off themandrel 12 by lifting on the tubing string. This permits the packerelement to contract and lets the expander cone slide upwardly frombehind the slip thereby permitting the slip to disengage from the wallof the well. Then teeth 48 on the slips are slanted downwardly tofacilitate their disengagement from the wall of the well when pulledupwardy. Should the packer fail to unset, a larger than normal force maybe applied upwardly on the mandrel which force is sufficient to shearthe pin 18 connecting the upper gauge ring to the mandrel. Shearing ofthis pin releases the upper gauge ring to permit decompression of theelastomer packing element thus releasing the sealing engagement.

The apparatus has thus far been described as being operated as acompression set packer. However, it is readily seen that by invertingthe apparatus on the tubing string, the packer may 'be set by applyingtension forces to the mandrel.

Referring now to FIG. 2 of the drawings, an alternate arrangement ofparts is shown which features a separate slip and drag block. The dragblock 54 is constructed from a unitary piece of material and has thesame slotted arrangement as shown with respect to the unitary member inFIG. 1. A drag block cage 56 is slidably received about the mandrel 12,the cage having overlapping flange members 58 which engage end tabs 59on the drag block to support the drag block on the packer. A J-pin 60which is connected to the cage 56 extends inwardly therefrom and ismovably received within J-slot 62 in the mandrel 12. A hook-shapedannular lug 64 extends upwardly from the cage and is received in acomplementary recess 6% on .a slip member 68. One end of slip member 68has a sloping portion 70 thereon which cooperates with op positelysloping portion 72 on the expander cone 74 positioned below the packerelement 76.

In the operation of the apparatus shown in FIG. 2, the

packer is run into the well bore to a point at which it is desired toexpand the packer. The mandrel is raised upwardly and rotated to movethe J-pin 60 into an elongated portion of the J-slot 62 whereupon themandrel is lowered. Lowering of the mandrel at this point causes theexpander cone 74 to move downwardly beneath the slips 68.'Tl1e slips areprevented from moving downwardly due to the frictional engagement of thedrag block 54 against the well bore. This downward movement of theexpander cone 74 earns the slips 68 outwardly into gripping engamementwith the well bore to anchor the slips therein. Continued downwardmovement compresses the packer element between the upper and lower gaugerings and radially expands the packer element 76 outwardly into sealingengagement with the well bore. The packer of FIG. 2 is unset in a mannersimiar to that set forth with respect to the operation of the apparatusof FIG. 1.

FIGS. 3, 4 and 5 show a shearing means to be used with a well tool suchas the packer. described herein. Referring to FIG. 3, the upper end of apacker mandrel 78 is shown attached to the lower end of a tubing 80. Apacker element 82 is shown positioned about the mandrel. An upper gaugering 84 is positioned over the end of the packer element. An annularrecess 86 is formed in the outer Wall of the packer mandrel. An arcuateshaped shear member 88 is positioned about the mandrel with the inneredge of the shear member fitted into the recess 86 on the mandrel. Aplurality of openings in the shear member receive screws 90 forfastening the shear member to the gauge ring 84. Radial slots or grooves92 (FIGS. 4, 5) are formed part way through the shear member '88 so thatportions or segments of the shear member may be easily broken therefrom.Each of the portions between the recesses 92 in the shear member has anopening for receiving a screw or bolt 90 to fasten each segment of themember to the gauge ring 84.

With the arrangement of shearing means as set forth above, the amount ofshear means needed in a well tool may be determined and selected at thewell location. The tool is shipped to the well location with a maximumamount of arcuate segments or shear means which would be needed in anysituation. The operator then removes segments of the arcuate memberuntil the number of the segments remaining corresponds to the shearvalue he wishes to provide on the tool. Each of the segments representsan equal amount of shear resistive material, for each segment mayrequire 10,000 pounds force to shear the segment. The grooves 92 in thearcuate shear member are sufficiently deep to permit the pieces to beeasily broken from the ring. As will be appreciated, the shear memberswould be placed about the mandrel in such a way as to balance ordistribute the shearing forces applied about the mandrel.

'Although the features of the invention herein have been described foruse with a packer, it is readily seen that such features would haveapplication to other well tools. Additionally, while particularembodiments of the present invention have been shown and described, itis apparent that changes and modifications may be made without departingfrom this invention in its broader aspects and, therefore, the aim inthe appended claims is to cover all such changes and modifications asfall within the true spirit and scope of this invention.

What is claimed is:

1. In a tool for use in a well; a body, a first member telescopicallymounted on said body and arranged for relative movement therewith, and ashear member coupled between said body and said first member in a mannerto prevent such relative movement, said shear member being responsive tosufficient force applied to said body and first member to shear andthereby permit relative movement between said body and first member,said shear member being weakened along lines radially dividing saidshear member into equal shear segments of predetermined shear strengththereby permitting said segments to be conveniently removed from saidshear member to change the amount of force required to shear said shearmember.

2. A packer for use in a well comprising: a body, packer means on saidbody including an elastomer packer element and expander means,selectively operable means for expanding said packer element intosealing engagement with the wall of the well, and shear means coupledbetween said body and packer means in a manner to prevent relativemovement between a portion of said packer means and said body, saidshear means being responsive to forces applied to said body to shear andthereby permit such relative movement, saidzshear means being comprisedof an arcuate member having weakened portions thereon dividing saidarcuate member into segments of equal shear strength, said weakenedportions permitting said segments of said arcuate member to beconveniently removed from said arcuate member and thereby change theamount of force required to shear said arcuate member.

3. A packer for use in a well comprising: a mandrel, first means on saidmandrel including drag block means for frietionally engaging the wall ofa well bore and slip means for gripping the wall of a well bore, secondmeans on said mandrel including al packer element and expander means,selectively operable means for permitting relative movement between saidfirst means and one portion of said second means to set said slip meansin gripping engagement with the wall of a well bore and to expand saidpacker element into sealing engagement with the wall of the well, saiddrag block means being a slotted annular sleeve which is compressibleabout said mandrel, annular groove means on said mandrel, and ashearable membericonnected to the other portion of said second means andfitted in said groove means to normally prevent rclative movementbetween said mandrel and said other portion, said shearable member beingresponsive to a certain force applied to said mandrel to shear andthereby permit such relative movement, said shearable member beingcomprised of an arcuate member having radial notches therein dividingsaid arcuate member into segments which permit such segmented portionsof said arcuate member to be conveniently broken OH to thereby selectthe amount of force required to shear said arcuate member.

References Cited UNITED STATES PATENTS 1,894,094 1/1933 Hackett 285-32,262,356 1/1941 Corey 2852 2,273,772 2/ 1942 Pollitz 62 X 2,282,6415/1942 Corey 285-2 3,018,830 1/ 1962) Springer 106-216 JAMES A. LEPPINK,Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,374,841 March 26 1968 James H. Current It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

In the heading to the printed specification, lines 3 and 4,"Schlumberger Well Surveying Corporation" should read S'ch'lumbergerTechnology Corporation Column 2, line 68, "ad rag" should read a dragColumn 3, line 20, "wall", second occurrence, should read well line 39,"What" should read When line 44, "Then" should read The line 46,"upwardy" should read upwardly line 58,

"alternate" should read alternative Column 4, line 11 "engamement"should read engagement tal-inc l6 "simiar" should read similar Signedand sealed this 26th day of August 1969.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. WILLIAM E. SCHUYLER,JR. Attestlng OfficerCommissioner of Patents

